Method and machine for forming flat bottom bags having side gussets

ABSTRACT

The machine first makes a strip of side gusset bags having two inwardly tucked panels forming each of the side gussets, the bags being interconnected with each other by cross-seals. A transfer splitter receives each leading bag at a pick off station prior to and during severing of the bag from the strip. The transfer splitter is operable to swing the severed bag into an upright position while keeping the gusset panels separated from each other. Grippers carried by a conveyor receive the bag from the transfer splitter and clamp the bag for step-by-step movement with the conveyor while keeping the panels separated from each other so as to permit subsequent expansion of the gussets to open the bag as it remains clamped to the conveyor. The lower end portion of the bag is folded upwardly and sealed to the one side of the bag to complete formation of the bag prior to the bag being opened and filled with a charge of product.

['111- 3,855,907 Dec. 24, 1974 United States-Patent [191 Johnson et al.

[ METHOD AND MACHINE FOR FORMING FLAT BOTTOM BAGS HAVING SIDE PrimaryExaminerR0y Lake GUSSETS Assistant Exam'inrJames F. Coan Inventors:

Attorney, Agent, or FirrnWol fe, Hubbard, Leydig, Voit & Osann, Ltd.

[75] Kenneth R. Johnson; Robert F.

Lense, both of Rockford, Ill.

[73] Assignee: Rexham Corporation, New York,

May 18, 1973 Appl. No.: 361,537

22 Filed:

each other by cross-seals. A transfer splitter receives each leading bagat a pick off station prior to and during severing of the bag from thestrip. The transfer splitter is operable to swing the severed bag intoan upright position while keeping the gusset panels separated from eachother. Grippers carried by a conveyor receive the bag from the transfersplitter and clamp the bag for step-by-step movement with the conveyorwhile keeping the panels separated from each other so References CitedUNITED STATES PATENTS as to permit subsequent expansion of the gussetsto open the bag as it remains clamped to the conveyor. T he lower endportion of the bag is folded upwardly and sealed to the one side of thebag to complete formation of the bag prior to the bag being opened andfilled with a charge of product.

7 Claims, 16 Drawing Figures PATENTED 083241974 v V////A kmgm -H....

PATENTED UEC24 I974 SWLUBBFT mEr-mu ww 3,855,907

swan s a? i METHOD AND MACHINE FOR FORMING FLAT BOTTOM BAGS HAVING SIDEGUSSETS BACKGROUND OF THE INVENTION This invention relates to a methodand a machine for forming bags from a continuous web of flexiblematerial and for filling each of the bags with a product.

More particularly, the invention relates to the manner in which the bagsare transported as they are formed, opened, filled and closed. Herein,the web is formed into a continuous fiat tube or strip having horizontalsides and inwardly tucked opposite edgeportions, each of the edgeportions including two facing panels which define an expandable gusset.Longitudinally spaced cross-seals are formed across the tube so the tubedefines a strip of interconnected bags. The bags are severed from theleading end portion of the strip by a cutter which slices through thestrip adjacent the trailing edge'of each cross-seal so one end of thenewly formed bag is unsealed.

Thereafter, the bags are turned into upright positions SUMMARY OF THEINVENTION The primary object of the present invention is to provide anew and improved machine of the above general type which is adapted tooperate in anovel manner to form flat bottom side gusset bags of thetype in which a lower margin of each bag is folded upwardly and sealedto one side thereof before the bag is opened to be filled. A moredetailed object is to adapt the foregoing machine in a manner such thatthe bags are partially formed in a bag making section of the machinewhile moving along a predetermined path and thereafter are transferredto a conveyor for movement along a contingether and sealed closed tocomplete the packaging operation.

The invention also resides in the provision of a unique transfersplitter operable to move back and forth between a pick off stationadjacent the downstream side of the cutter and oneend of the firstconveyor to swing the bags from their horizontal positions into theirupright positions while keeping the adjacent BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1a is a schematic perspective view of the bag formingportion of a machine embodying the novel features of the presentinvention.

FIG. lb is a continuation of FIG. la and is a schematic view of thebag-filling andbag-closing portion of the machine. I

FIG. 2 is a perspective view of a'bag after being formed, filled andclosed by the machine. FIG. 3 is an enlarged cross-sectional view takensubstantially along line 33 of FIG. 1&1.

FIG. 4 isan enlarged cross-sectional view taken substantially along line4 4 of FIG. la.

FIG. 5 is a fragmentary perspective view of a partially .formed bag madeby the machine.

FIG. 6 is an enlarged fragmentary perspective view of I a transfersplitter for transporting partially formed bags uation of the paththrough a filling station, the formation of the bottoms of the bagsbeing completed while being advanced by the conveyor and before the bagsare opened to receive the measured charge of product.

A further object is to construct the machine so the two panels formingeach of the side gussets are kept separated from each other as the bagsare transferred from the-bag making section of the machine to theconveyor.

A still further object is to hold the bags in their upright positions onthe conveyor so that, without releasing the bags from the conveyor, theformation of the bottoms of-the bags may be completed and thereafter theside gussets may be expanded to open the bags for filling.

Another detailed object of the present invention resides in theprovision of a second conveyor adapted to receive the filled bags fromthe first conveyor and to transport the filled bags through successivestations where the upper margins of the bags are folded tofromhorizontal to upright positions.

FIG. 7 is a fragmentary perspective view similar to FIG. 6, but showingparts of the machine in moved positions. e

FIG. 8 is an enlarged cross-sectional view taken substantially along 88of FIG. 7.

FIG. 9 is an enlarged fragmentary perspective view showing parts of aflying splitter for guiding the partially formed bags onto the transfersplitter.

FIG. 10 is an enlarged fragmentary perspective view schematicallyshowing parts of the machine for completing the formation of thebottomsof the bags prior to the bags being completely opened.

FIG. 11 is an enlarged fragmentary cross-sectional view takensubstantially along line 11-11 of FIG. 10. I

FIG. 14 is a view similar to FIG. 13, but showing parts in movedpositions.

FIG. 15 is an enlarged schematic view showing the bag closing andbag-sealing stations of the machine.

DETAILED DESCRIPTION OF THE PREFERRED- EMBODIMENT I As shown in thedrawings for purposes of illustration,

the present invention is embodied in a machine 20 particularly adaptedfor forming, filling and closing side gusset bags 21 having fiat bottoms22. As shown in FIGS. 2 and 3, each bag comprises two opposingfaceto-faces'ides 26 and 27 joined together along their two side marginsby gussets 33 and along their bottom margins by a lower seal 51. Theupper margins 163 of the sides are sealed together to close the bag. Ineach completed, filled and closed bag, the gussets are expanded andtriangular portions 170 (FIG. of the top margins of each gusset andsimilar portions (not shown) of the bottom margins of each gusset aredisposed inwardly to shape the bag as a block. More particularly, thelower seal 51 extends across. the bottom 22 of the bag between thegussets and each gusset is defined by two adjacent side panels 42 joinedtogether along a fold line28.

Basically, the machine comprises a bag-making heat sealable along oneside thereof is formed into a continuous strip 23 of interconnectedbags. To form the strip of bags, the web is advanced intermittently pastand is folded around a tube former 25 to bring the opposite edgeportions of the web into overlapping relation to form the opposing sides26 and 27, the latter' side being interrupted by a longitudinal seam 29defined by the overlapped edge portions of the web. As shown in FIG. 1a,the tube-former includes a' forming wheel 30 under which the web feedsso opposite edge portions of the web are dished upwardly. Upon leavingthe wheel, the web passes beneath and alongside a forming plate 31, thedished edge portions being folded gradually around the plate and into anoverlapping relation to form the web into a flat tube with the seam 29facing upwardly. h

To form the tube with the side gussets 33, the opposite edge portions ofthe tube are tucked inwardly in a V-shape as shown in FIG. 3. For thislatter purpose, the forming plate 31 comprises a narrow center section34 sandwiched between upper and lower sections 35 which are sider thanthe center section so as to define elongated grooves 36 extending alogopposite side edges of the plate. The upstream end of the plate issupported by a leg 37 (FIG. la) secured to the upper section 35 whilethe downstream end of the plate is supported by two rollers 39 which aredisposed on opposite sides of the plate and extend laterally of thetube. As the 'web 24 is advanced beneath the forming plate, itslongitudinal edge portions are tucked into the grooves by elongatedstationary splitters 40 projecting inwardly into the grooves between theupper and lower plate sections. each of the side gussets 33 thus beingformed with the panels 42 facing each other. Above the splitters arefour forming disks 41 which exert frictional forces on the web tendingto wrap the same gradually around the top of the plate. Pressing fingers43'are disposed between the pairs of disks and overlie and hold the webas it passes between the disks.

Downstream of the disks 41, an electrically heated sealing bar 44 (seeFIGS. 1a and 3) is brought downwardly into engagement with the upperside 27 of the web or tube 24 along the seam 29 to seal, together themoved up and down to engage and release the tube by pneumatic actuators46 and 47 which are controlled in .timed relation with the advance ofthe tube.

In a similar manner, a heated cross-sealing bar 49 and a lateral coolingbar 50 located downstream of the (plate 31 are actuated to pinch theopposite sides 26 and 27 of the tube 24 together to form spacedcross-seals 51 (see FIGS. 1 and 5). In this way, the tube is formed intothe strip 23 of interconnected bags 21 which are subsequently severedfrom each other. At the same time the cross-seal is formed in eachbag,-the crosssealing bar also forms a slanted seal 52 between the lowermargin ofeach panel 42 and the adjacent side 26 or 27.of the bag, eachslanted seal extending upwardly and outwardly from the lower end of thefold line 28 to the edge between the panel and the side of the bag Thespace between the two slanted seals on each gusset 33 defines thetriangular portion which is to be disposedinwardly on the bottom marginof thegusset. In addition to cooling the hot cross-seal and slanted.seals in each bag, the cooling bar 50 alsoforms a crease 53 (FIG. 5) inthe tube along the upstream edge of the cross-sealwhen advanced againstthe bag so as to later facilitate folding of the bottom margin upwardlyalong the side 27 of the bag. 7 v

Downstream of the cooling bar 50, mechanism in the form of twohorizontal drive rollers 54 (FIG. la) frictionally engages the oppositesides 26 and 27 of the bags to advance the strip 23; The rollers arerotated intermittently through preciselycontrolled angular distances tofeed the strip through steps exactly equal in length to the length ofthe bags. Herein, the rollers are connected to a motor 55 by a powertrain 56 operable to drive the rollers intermittently in response tomeasured movement of the strip of bags as detected by a photoelectricscanner 57 supported above the bags.

A cutter 63 (FIG. 1a) in the cutting station severs the leading bag 21in the strip 23 from the other bags by cutting the strip alongside andjust behind the trailing edge of each cross-seal 51 so one end of the.bag is sealed by the cross-seal and the other end of the bag isunsealed. Each bag, after being cut from the strip, is turned into anupright position so the sealed end of the bag forms a lower margin64(see FIG. 7).and the unsealed end of the bag faces upwardly. Thereafter,a

conveyor 65 advances'the upright bag in an edgewisev directionstep-by-step through a filling station 66 (see FIG. 1b). In thisinstance, the conveyor includes an endless chain 67 traveling in ahorizontal plane and trained around sprockets 69 and 70, the sprocket 69being positioned adjacent and below the pick off station 61 such thatone of the curved end runs of the chain isspaced downstream of andbeneath the horizontally disposed bags cut from the strip 23 at thecutting station 60.A Geneva mechanism 71 coupled tothe sprocket isdriven by a cycle 'shaft 72 and is timed to advance the chainintermittently at approximately the same time the drive rollers 54 areadvancing the strip so both the chain and the drive rollers dwell duringthe same intervals.

In accordance with the primary aspect of the present invention, themachine is adapted to operate in a novel manner so as to completeformation of each of the bags 21 by folding the lower margin 64 of thebag upwardly and sealing the margin to the side 27 of the bag as thelatter is advanced along the fill section 38 of the machine but beforethe bag is opened to be filled. For this purpose, a unique transfersplitter 73 (FIG. lb) swings each of the partially formed bags from thepick off station 61 of the bag making section 32 into an uprightposition of the conveyor for grippers 74 to clamp the bags for movementwith the conveyor. Advantageously, the transfer splitter keeps the twofacing panels 42 in each gusset 33 separated from each other as the bagis swung from the pick off station to the conveyor so the grippers canclamp the bag along its edges to permit the lower margin of the bag tobe folded upwardly and sealed to the side of the bag whilestill keepingthe two panels in each gusset separated from each other. This permitssubsequent expansion of the gussets to open the bag for receiving theproduct charge as the bag remains clamped to the conveyor. Thus, withthis arrangement, the machine 20 is adapted for use in formingflat-bottom bags by completing formation of the bottom 22 of the bagafter the latter is transferred from thebag making section of themachine.

.In the present instance, the transfer splitter 73 is swung from thepick off station 61 to carry each bag2l to the conveyor 65 during thedwell period and includes spaced parallel blades (see FIGS. 6 and 7)supported on pivot arms 76 by links 77. The blades fit between thegusset panels 42 along opposite edges of the bag, and suction cups 79help hold the bag on the blades as the splitter swings toward theconveyor. Herein, a flying splitter 80 guides the end bag of the strip23 from the downstream'ends of the stationary splitters 40, through thecutting station 60 and into the pick off station. Upon reaching-the pickoff station, the flying splitter abuts the transfer splitter 73 (seeFIG. 9) so that, as the strip advances further into the pick offstation, the panels 42 slide telescopically onto the blades so thelatter keep the panels separated from each other.

Prior to severing the end bag 21 from the strip 23, the flying splitter80 is retracted relative to the strip, back upstream of the cutter 63and into position to guide the next bag into the pick off station 61during the next advance of the strip. Herein, the flying splitter isreciprocated by a fluid-actuated cylinder 81 with each advance step ofthe strip and includes a split upstream end portion 83 (see FIG. 9)sandwiched over a portion 84 of the stationary splitter 40 to guide theflying splitter as it'moves back and forth through the cutting station60.

To swing the bag 21 into its upright position, the arms 76 of thetransfer splitter 73 are supported on a horizontal rock shaft 85 (FIG.6). The latter is connected through linkage 86 to a follower 87 (FIG.lb) which engages a cam 89 on the cycle shaft 72. Accordingly, duringthe dwell period, the shaft 85 is pivoted first in a counterclockwisedirection (FIG. 6) to swing the blades 75 and the bag into verticalpositions at the end of the conveyor 65 and then, after the bag isclamped for movement with the conveyor, the blades are swung clockwise(FIG. 7) back to the ceive the next bag.

As, the bag 21 reaches its vertical position, the grippers 74 (see FIGS.7 and 8) grasp .the bag along the opposite edges thereof to hold the bagfor movement with the conveyor 65. Herein, the grippers are pivotallysupported on a yoke 90 (FIG. 7) attached to one of the links 91 of theconveyor chain 67 and normally are biased closed by springs 93. As shownin FIG. 8, each gripper includes a generally V-shaped bellcrank 94, oneend of which forms a jaw 95 which coacts with the yoke to grip the bag.Herein, the jaws extend through notches 96 in the blades 75 so that onlyone panel 42 is clamped between the jaw and the yoke along each edge ofthe bag. Tov open the jaws to receive the bag, a follower 97 on theother end of the bellcrank94 is engaged by a cam 99 which, when advancedtoward the follower by an actuating linkagel00 (FIG. 1b), overcomes thesprings to pivot the jaws open to receive the bag. In the exemplaryembodiment, the actuating Iinkage is moved back and forth by a face cam10 1 mounted on the cycle shaft 72.

After the grippers 74 grasp the bag 21 for movement with the conveyor65, the splitter 73 is swung back to the pick off station 61.Thereafter, the conveyor is advanced to cause thelower margin 64 of thebag to ride pick off station to reover a folding bar 103 (FIG. 10) andto be folded upwardly along the crease 53 and into a substantiallyhorizontal position as the bag is advanced ,into a gluing station 104.At the gluing station, applicator nozzles 105 spray hot-melt adhesive ina strip-106 across the bag and above the crease so the lower margin canbe glued to the side 27 of the bag. As the bag is moved out of thegluing station, the bar 103 folds the lower margin upwardly so as toparallel the side of the bag preparatory to entering a sealing station107. In the sealing station, jaws 109 and 110 ofa pressing mechanism 111are closed by an actuator 113 (see FIG. 11) and squeeze folded marginagainst the side of the bag so the adhesive seals the margin to the sideof the bag so as to com,- plete the formation of the bottom of the bagprior to opening the latter.

Once the bottom of the .bag 21 has been forme'd,-the conveyor 65advances the bagintoan opening station 114 where, during the dwellperiod, an opener 115 (FIGS. 12 and 13) is telescoped downwardly intothe I bag and is actuated to expand the gussets 33 to open the bag.Herein, the bag opener includes two plates 116 pivotally mounted onopposite sides of a support 117. Intermediate their ends,the plates arebent toward each other (see FIG. 13) to permit easy entry of the platesinto the bag as the support is advanced downwardly from a retractedposition above the bag by a fluid-operated cylinder 119. The support iscarried slidably on the end of a rod 120 projecting downwardlyfrom .thecylinder and is located between upper and lower stops 121 and 123secured to the lower end portion of the rod. A spring 124 acting betweenthe upper stop 121 and the support urges the latter downwardly intoengagement with the lower stop 123. Also connected to the lower end ofthe rod are two sets of curved arms 125 see FIG. 12) whose lower endsare pivotally fastened to the plates, one set of the arms being fastenedto one of the plates adjacent the bend in that plate andthe other set ofarms being fastened in a like manner to the other plate. Slots 126 (FIG.13) in the upper ends of the arms receive a pin 127 which tance whichthe arms can pivot away from each other is limited by the support 1 17as it compresses the spring .124 against the upper stop 121.

To limit downward movement of the support 117 so the downwardly movingrod '120 may overcome the spring 124 and slide downwardly relative tothe support to spread the arms 125, two vertical guide bars 129 (FIG.12) on opposite sides of the rod 120 are fixed at their lower ends tothe support 117 and are bushed slidably by a fixed bracket 130 whichalso supports the cylinder 119. Threaded on the upper ends of the barsare stop nuts 131 which, when the support is pushed downwardly by therod, engage the upper surface of the bracket to prevent further downwardmovement of the support. At this point, the rod overtravels to spreadthe arms and plates 116 (see FIG. 14) and thereby to open the bag 21.As'the gussets 33 are expanded in this manher, a horizontal kicker plate134 (FIGS. 1b and 14) strikes the bottom of the bag to help square thebag before the latter is advanced out of the bag opening station 114.The plate 134 is carried on the end of a rod 135 adapted to bereciprocated upwardly and downwardly by a cam 136 on the cycle shaft 72.

As the open bag 21 is advanced out of the bag opening station 114 by theconveyor 65, a U-shaped holder 137 (FIG. 12) carried on a chain 139 ofanother conveyor 140 swings upwardly along each of the gussets 33 toadvance the bag along its predetermined path to be filled andsubsequently closed. The second conveyor is advanced step-by-step intimed relation with the first conveyor through suitable mechanism (notshown) and includes one end sprocket 141 (see FIG. lb) spaced betweenthe sprockets 69 and 70 of the first conveyor and an opposite'endsprocket (not shown). The chain 139 is trained around the two sprocketsof the second conveyor and carries a bracket 143 (FIG. 12) to which theholder is secured for pivotal movement between a downwardly opening.vertical position and a horizontally openingposition disposed aroundthe bag. The holder is urged into its normal horizontal position by aspring 144 (FIG. 13) acting between the bracket and the holder but, inthe bag opening station 114,- the holder is held downwardly in itsvertical position by a retaining bar 145 (FIG. 12). The latter ispositioned such that, in the bag opening station, the holder is tiltedslightly upwardly along the gussets 33 and, as the bag leaves theopening station, the holder passes by the end of the bar to swingupwardly along the-bag under the urging of the spring. At this point,the grippers 74 are still clamping the bag 21 on the first conveyor 65and thus retain the bag within the holder 137 as the two conveyors 65and 140 advance the bag into the filling station 66. Upon being advancedout of the bag opening station 114, the bag is slid onto two drivenbelts 146 which are separated from each other and which keep the bagfrom falling downwardly out of the holder during subsequent advance ofthe bag. The belts are trained around a pulley 147 and advanced in timedrelation with the second conveyor to avoid relative sliding between thebelts and the bottom 22 of the bag.

on the front side 27 of the bag as the grippers 74 capti-' vate the bagin the holder 137. Then, a charge of product is fed into the bag from adispenser 150. To help the product settle within the bag, a kickerplatform 151 is mounted beneath the two belts 146 and is jogged upwardlyagainst the belts by a cam 153 FIG. 1b) mounted on the cycle shaft. 72.

As the bag 21 is advanced from the filling station 66 by the twoconveyors'65 and 140, the followers 97 on the grippers 74 of the firstconveyor engage a sta-, tionary cam 154 (FIG. 12) mounted above the endsprocket and are opened sothe grippers release the bag. The latter isthen carried solely by the second conveyor and the belts 146 and isadvanced step-bystep through closing, sealing and flattening stations155,156 and 157 (FIGS. 16, 12 and 15). In the closing station 155,pivoted L-shaped gusset tuckers 159 (FIG.

12) engage the two side gussets 33 between each of the two panels 42adjacent the top of the bag and tuck the gussets toward each other 'toassure that the bag will close properly. After the gussets have beentucked inwardly, closing bars 160 are advanced by a cam 161 (FIG. 1b) toengage the opposite sides 26 and 27 of the bag along the upper margins163 thereof and crimp the bag closed. As this is done, a second kickerplatform 164 is jogged upwardly from beneath the two belts 146 by a cam165 and helps to settle the product within the bag.

The bag 21 then is advanced from the closing station 155 with the uppermargin 163 being sandwiched between two parallel guide bars 166 (FIGS.12 and 15) to keep the upper end of the bag from expanding open as thebag is carried into the sealing station 156 by the second conveyor 140.In the sealing station, two sealing bars 167 are advanced to seal thetop margins of the two side panels 26 and 27 together to close the bag.As the bars are sealing the sides together, squaring arms 169 (FIG.15)adjacent each end of the top seal being formed are swung toward eachother to expand the upper portion of each gusset 33 while also tuckingthe triangular portion 170 atthe upper end of each gusset inwardlybeneaththe margins to help square the top of gripped by a suction device149 which pulls outwardly the bag. As the arms reach the ends of theirinward swinging, a jogging platform 171 beneath the sealing station islifted into engagement with the belts 146 to push the bag upwardly sothe top portion of the bag is pressed against the sealing bars and thearms to square the top of the bag. Thereafter, the arms, the joggingplatform and the sealing bars are retracted away from the bag and thelatter is advanced to the flattening station 157 to fold the uppermargins, now forming a top seal 163, downwardly-onto the top of the bagas is shown in FIG. 15. The bag subsequently is removed from the machinefor placement into shipping cartons.

From the foregoing, itwill be apparent that the machine 20 of thepresent invention is adapted to operate in a novel manner so as toutilize the bag making section 32 in the formation of the flat-bottomside gusset bags 21. To this end, the bottoms 22 of the'bags arecompleted by folding the lower margins 64 of the bags upwardly alongthe'sides 27 of the bags as the latter are advanced along the fillsection 38 of the machine but before the bags are opened to be filled.By utilizing the novel transfer splitter 73 to keep the gusset panels 42separated from each other as the bags are carried from the pick offstation 61 to the conveyor 65, the grippers 74 may be actuated to clampthe bags for movement with the conveyor without clamping the gussetsclosed. Advantageously, this enables the bottoms of the bags to becompleted along the fill section of the machine while still permittingthe bags to be opened subsequently for filling without need ofunclamping the bags from the conveyor.

We claim as our invention:

1. A method of forming flat bottom, side gusset bags from a strip ofinterconnected bags, said strip having cross-seals connecting said bagstogether and having side gussets along opposite margins and each definedby two inwardly tucked panels which face one another, said methodcomprising the steps of, advancing said strip along a predeterminedpath, guiding the leading bag insaid strip intoa pick off station,separating the two panels of each of the gussets from each other as thebag is moved into said station, severing the leading bag from said stripadjacent said station along the edge of one of said cross-seals to leavethe severed bag with one end closed by one of said cross-seals and withthe other end unsealed, swinging said severed bag from said pick offstation onto a conveyor, keeping each of the two panels separated fromeach other as said bag is swung from said pick off station onto saidconveyor, clamping said bag on said conveyor, maintaining each of saidtwo panels separated from each other as said bag is clamped to'saidconveyor so as to permit subsequent expansion of said gussets to opensaid bag as the latter remains clamped to the conveyor, advancing saidconveyor to carry said bag along a continuation of said path, folding aportion of the sealed end of the bag along one side of the bag while thebag is clamped to said conveyor, and sealing said portion against theside of the bag to complete formation of the sealed end of the bagprior-to opening and filling of the bag.

2. A method of forming side gusset bags from a strip of interconnectedbags,,said strip having cross-seals connecting said bags together andhaving side gussets along opposite margins and each defined by twoinwardly tucked panels which face one another, said method comprisingthe steps of, advancing said strip step-by-step along a horizontal pathwith the bags disposed in horizontal positions, guiding the leading bagin said strip into a pick off station, separating the two panels of eachof the gussets from each other as the bag is moved into said station,severing the leading bag from said strip adjacent said pick off stationalong the edge of one of said cross-seals to leave the severed bag withone end closed by one of said cross-seals and with the other endunsealed, swinging said severed bag from said pick off station into anupright position on a conveyor while keeping each of the two panelsseparated from each other, gripping only one of the panels in eachgusset to clamp the bag on the conveyor while still keeping the twopanels in each gusset separated from each other to permit subsequentexpansion of said gussets to open said bag as the latter remains clampedto the conveyor, advancing said conveyor step-by-step to carry said bagalong a horizontal path with the bag in an upright position, applyingadhesive across the bag adjacent the sealed end thereof, folding aportion of the 1 sealed end of the bag upwardly along one side of thebag, and pressing said folded portion against the side of the bag tocause the adhesive to seal the folded portion to the side of the bag tocomplete formation of the bag prior to opening and filling of the bag.

3. A method of forming side gusset bags as defined by claim 2 furtherincluding the steps of opening each bag after completing the formationof the bottom of the bag, squaring the bottom of the bag as the latteris opened, and filling the bag with a product. 7

4. A method of forming side gusset bags as defined by claim 3 furtherincluding the steps of transferring the bag onto a second conveyor,holding the bag for movement with said second conveyor, unclamping saidbag from said first conveyor after filling the bag, advancing saidsecond conveyor in timed relation with said first conveyor, tucking thegussets toward each other adjacent the top of said bag, and sealingtogether the upper end portion of the opposite sides of said bag toclose the bag.

5. A machine for forming side gusset bags from a strip of interconnectedbags, said strip having crossseals connecting said bags together andhaving side gussets along opposite margins and each defined by twoinwardly tucked panels'which face one another, said machine includingmeans for advancing said strip stepby-step along a predetermined pathinto a pick off station, a splitter sandwiched between the two facingpan- .els of each gusset and operable to keep the panels separated asthe leading bag is advanced into the pick off station, a cutter adjacentsaid pick off station and operable to sever the leading bag from saidstrip along one edge of one of said cross-seals to leave the severed bagwith one end closed by one of said cross-seals and with the other endunsealed, a transfer splitter receiving said leading bag at said pick'off station prior to cutting of the bag, said transfer splitter beingsandwiched between the two facing panels of each gusset and beingmovable from said pick off station to swing the severed bag into anupright position while keeping each of the two panels separated fromeach other, a conveyor having one end located adjacent said pick offstation and operable to move said bag step-by-step along a continu-'ation of said path in timed relation with the advance-- ment of saidstrip, grippers carried by said conveyor and operable to clamp said bagin its upright position for movement with said conveyor, said gripperskeeping each of said two panels separated from ,each other so as topermit subsequent expansion of said gussets to open said bag as thelatter remains clamped to said con veyor, means for folding a portion ofthe sealed end of said bag upwardly against one side of the bag, andmeans for sealing said folded portion to the side of the bag to completeformation of the bag prior to opening and filling of the bag.

6. A machine as defined by claim 5 further including means-for applyingadhesive across said bag adjacent,

the sealed end thereof prior to folding said portion of the sealed endagainst the side of the bag.

7. A machine as defined by claim 6 wherein said conveyor advances saidbag through an, opening station and a filling station, a bag openerlocated at said opening station, adapted to open said bag and to squarethe bottom of the bag, a dispenser located at said filling station andoperable to deposit a charge of product into said bag, and a secondconveyor operable in timed relation with said first conveyor forreceiving said bag from said first conveyor and holding said bag foradvancement along a further continuation of said path to be sealedclosed.

1. A method of forming flat bottom, side gusset bags from a strip ofinterconnected bags, said strip having cross-seals connecting said bagstogether and having side gussets along opposite margins and each definedby two inwardly tucked panels which face one another, said methodcomprising the steps of, advancing said strip along a predeterminedpath, guiding the leading bag in said strip into a pick off station,separating the two panels of each of the gussets from each other as thebag is moved into said station, severing the leading bag from said stripadjacent said station along the edge of one of said cross-seals to leavethe severed bag with one end closed by one of said cross-seals and withthe other end unsealed, swinging said severed bag from said pick offstation onto a conveyor, keeping each of the two panels separated fromeach other as said bag is swung from said pick off station onto saidconveyor, clamping said bag on said conveyor, maintaining each of saidtwo panels separated from each other as said bag is clamped to saidconveyor so as to permit subsequent expansion of said gussets to opensaid bag as the latter remains clamped to the conveyor, advancing saidconveyor to carry said bag along a continuation of said path, folding aportion of the sealed end of the bag along one side of the bag while thebag is clamped to said conveyor, and sealing said portion against theside of the bag to complete formation of the sealed end of the bag priorto opening and filling of the bag.
 2. A method of forming side gussetbags from a strip of interconnected bags, said strip having cross-sealsconnecting said bags together and having side gussets along oppositemargins and each defined by two inwardly tucked panels which face oneanother, said method comprising the steps of, advancing said stripstep-by-step along a horizontal path with the bags disposed inhorizontal positions, guiding the leading bag in said strip into a pickoff station, separating the two panels of each of the gussets from eachother as the bag is moved into said station, severing the leading bagfrom said strip adjacent said pick off station along the edge of one ofsaid cross-seals to leave the severed bag with one end closed by one ofsaid cross-seals and with the other end unsealed, swinging said severedbag from said pick off station into an upright position on a conveyorwhile keeping each of the two panels separated from each other, grippingonly one of the panels in each gusset to clamp the bag on the conveyorwhile still keeping the two panels in each gusset separated from eachother to permit subsequent expansion of said gussets to open said bag asThe latter remains clamped to the conveyor, advancing said conveyorstep-by-step to carry said bag along a horizontal path with the bag inan upright position, applying adhesive across the bag adjacent thesealed end thereof, folding a portion of the sealed end of the bagupwardly along one side of the bag, and pressing said folded portionagainst the side of the bag to cause the adhesive to seal the foldedportion to the side of the bag to complete formation of the bag prior toopening and filling of the bag.
 3. A method of forming side gusset bagsas defined by claim 2 further including the steps of opening each bagafter completing the formation of the bottom of the bag, squaring thebottom of the bag as the latter is opened, and filling the bag with aproduct.
 4. A method of forming side gusset bags as defined by claim 3further including the steps of transferring the bag onto a secondconveyor, holding the bag for movement with said second conveyor,unclamping said bag from said first conveyor after filling the bag,advancing said second conveyor in timed relation with said firstconveyor, tucking the gussets toward each other adjacent the top of saidbag, and sealing together the upper end portion of the opposite sides ofsaid bag to close the bag.
 5. A machine for forming side gusset bagsfrom a strip of interconnected bags, said strip having cross-sealsconnecting said bags together and having side gussets along oppositemargins and each defined by two inwardly tucked panels which face oneanother, said machine including means for advancing said stripstep-by-step along a predetermined path into a pick off station, asplitter sandwiched between the two facing panels of each gusset andoperable to keep the panels separated as the leading bag is advancedinto the pick off station, a cutter adjacent said pick off station andoperable to sever the leading bag from said strip along one edge of oneof said cross-seals to leave the severed bag with one end closed by oneof said cross-seals and with the other end unsealed, a transfer splitterreceiving said leading bag at said pick off station prior to cutting ofthe bag, said transfer splitter being sandwiched between the two facingpanels of each gusset and being movable from said pick off station toswing the severed bag into an upright position while keeping each of thetwo panels separated from each other, a conveyor having one end locatedadjacent said pick off station and operable to move said bagstep-by-step along a continuation of said path in timed relation withthe advancement of said strip, grippers carried by said conveyor andoperable to clamp said bag in its upright position for movement withsaid conveyor, said grippers keeping each of said two panels separatedfrom each other so as to permit subsequent expansion of said gussets toopen said bag as the latter remains clamped to said conveyor, means forfolding a portion of the sealed end of said bag upwardly against oneside of the bag, and means for sealing said folded portion to the sideof the bag to complete formation of the bag prior to opening and fillingof the bag.
 6. A machine as defined by claim 5 further including meansfor applying adhesive across said bag adjacent the sealed end thereofprior to folding said portion of the sealed end against the side of thebag.
 7. A machine as defined by claim 6 wherein said conveyor advancessaid bag through an opening station and a filling station, a bag openerlocated at said opening station, adapted to open said bag and to squarethe bottom of the bag, a dispenser located at said filling station andoperable to deposit a charge of product into said bag, and a secondconveyor operable in timed relation with said first conveyor forreceiving said bag from said first conveyor and holding said bag foradvancement along a further continuation of said path to be sealedclosed.